Pour oil into a wok or large skillet. (If necessary, add more oil during cooking.) Heat over medium-high heat. Add red onion, green onions and garlic to wok; cook and stir for 2 minutes or until just tender. Remove vegetables from wok.

Add chicken to wok; cook and stir for 2 to 3 minutes or until no longer pink. Push chicken from center of wok. Stir sauce; add to center of wok. Cook and stir until bubbly. Return cooked vegetables to wok. Add water chestnuts and dried chile peppers, if you like. Cook and stir about 1 minute more or until heated through. Remove large pieces of chili pepper, if using. Stir in cashews. Serve with rice. Serves 4.